Electromagnetic sound-producer.



' L. GRUBMAN.

l-LECTROMAGNETICl SOUND PRODUCER.

APPLICAUON FILED MAY 2s. 1914.

l 913,30 Patented June 15, 1915.

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WITNESS/:"8: l A /lV VEN TUR A TOHNEY fio einen,

LEO GRUIBMAN, 0F NEW YORK, N. Y., A SSGNOR TO ELECTRIC SPARK APPLMNCE CQ., INC., 0F NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

ELECTROMAGNETIC SOUND-PRODUCER.

intense.

Specication ofY Letters Patent.

Patented J une 15, 1915s Application led May 23, 1914. Serial No. @$0,431.

To all whom 'it may concern:

Be it known that I, LEO GRUBMAN, a citizen of the United States, and a resident of the borough of Brooklyn, county of Kings, city and State of New York, have invented certain neii7 and useful Improvements in lllectromagnetic Sound-Producers, of which the following is a specication.

lily improvements relate to the type of rcsonating devices, set forth in my concurrent application No. 825,114, filed Mar. 16th, 1914, in which a diaphragm is caused to vibrate by electi'o-inagnetic means, as for instance in connection with horns for directing sound warnings, and for analogous purposes, Ithe object in the present case being the simplification of structure by eliininating intermediate instrumentalities 'between the armature and the diaphragm actuated thereby, and the concentration and augmentation of the electro-magnetic force as applied to said armature, as hereinafter more fully set forth; and other incidental fea-- tures of the invention relating to the specific construction and arrangement of parts described and claimed.

ln the accompanying drawings, Figure 1, is a central sectional elevation of an automobile horn embodying the essential features of my invention, parts being shown symbolically: Fig. 2, is a rear View with back casing reiiioi'ed; Fig. 3, is a rear view, the armature and connections beingr omitted, and the remaining parts beine; successively broken away to show their relative arrangement.

The horn H, is attached centrally to the annular front plate F, formed with the peripheral flange Resting against the rear side of the. front plate F, is the spacing pad f", the edges ol the elastic resilient diaphragm l), beingl between said pad f, and a companion spacing pad f2. The inner peripheral edge l', ot the back cap or rear casintr li, fits within the flange f, of the front plate F, and rests against the rear of the said )second spacing,r pad f2. The electroinagret M, is also positioned against the said inner spacing pad f2, and is of peculiar construction in that it consists preferably of two annular disks 'm1, m', spaced apart by the annular magnetic block m2. Between thc members m, m, of the magnet is the electric com; C, centralized and held in place lynn izvlindrical tube of insulating;i material i`l1e inner edges of the magnet member m', adjacent to the diaphragm protrude inward slightly beyond the insulating tube ma, into relatively close proximity to the strikingl end a, of the armature A, Which striking end a, is preferably rounded or dome shaped as shown in Fig. 1, to form an apex for direct intermittent contact with the dia phragm under the impulses imparted by the electrical coil in the usual and Well known manner. This rounded or dome shape of the striking face a, of the armature A, admits of the shaping of the inner edges m,

of the magnet plate m, in close conformity vcentral space between the actuating,` coil and the magnetic poles, and in utilizing the armature itself directly. and Without any intervening instrumentality, as the actuating v hammer for the diaphragm D. By this means the construction and operation of parts is greatly siinplilied and rendered more effective, since an intervening plunger or equii-'alent motion-transinitting device is dispensed with, and the arrangement is rendei-ed more compact, with the armature, to all intents and purposes, positiened practically hetween the magnetic poleshii'here it is not only influenced by the latter but by the coil also, acting as a solenoid. i

As in my concurrent application hereinbefore referred to'the armature is mounted upon a retractile spring a', and the make and break or current-interrnpting means may be essentially the same as in my concurrent application therein set forth, or of positioning' other fthan the rounded or dome shape shownv Fig. l, with like result, so that I do not glimit myself in this respect, nor to other non-essential details of construction.

WhatlI claim as' my invention and desireto secure by Letters Patent is,

1. In electro-magnetic sound producers of the character designated, in combination, an electric coil, a casing of magnetic material inclosing said coil, said casing being formed With a central opening substantially in axial coincidence with the central opening in said coil, a'retractile armature of magnetic material positioned mainly in said central space between said coil andicasing, and an elastic resilient diaphragm rlthe armature having its end positioned to irectly strike said diaphragm, for the purpose described.

2. In electro-magnetic sound producers of the character designated, in combination, an elastic resilient diaphragm, a retractile hammer-armature of magnetic material having i its end positioned to directly strike said diaphragm, and an electro-magnet one pole of which is in close proximity to the portion of the hammer-armature which contacts directly and intermittently Vwith said dia phragm.

8; In electro-magnetic sound producers of the character designated, in combination, an electro-magnet consisting essentially of two parallel disks formed With central openings, an annular spacing block between them, an electric coil positioned between them with its central opening in axial coincidence with the openings in the magnet plates, a retractile hammer-armature of magnetic materialpositioned mainly Within said'central space between the magnetic plates and coil,

and an elastic resilient diaphragm, the armature having its end positioned to directly strike said diaphragm, for the purpose described.

4. In electro-magnetic sound producers ot the character designated, an elastic resilient diaphragm, a retractile hammer-armature of magnetic material having its end positioned to directly strike said armature and formed with a convergent striking face, and an electro-magnet, a portion of which protrudes between said diaphragm and said convergent striking face, said convergent face positioned Within a central opening in said magnet.'

5. In electro-magnetic sound producers of the character designated, an elastic resilient diaphragm, electrounagnet having an electric coil centralized in said. magnet, a retractile hannner-armature et magnetic material haring its end positioned to directlyy e0 strike said diaphragm, said end being -rnovable through sai'd magnet and coil,

6. In electro-magnetic sound producers of the character designated., an elastic resilient diaphragm, an 'elec'tro fmagnet having an 65 electric coil centralized in said magnet, a retractile hanimer-armature of -ma-gnetic material Vharing its end positioned to directly strike said diaphragm, said 'end being movable through said magnet and coil,

and a tube of insulating material centraliz ing and holding said coil in place.

i. In electric-znagnetic sound producers of the character designated, an elastic resilient diaphragm, an electro-m electric coil centralized insaid magnet, a retractile hammenarmature of magnetic inaterial having its end positioned to directly strike said diaphragm, said end being movable through said magnet and coil, the striling face of said armature being rounded and the inner edges of the portion of the magnet adjacent the diaphragm being shaped in close conformity thereto.

8. In electro-magnetic sound producers of the character designate'an elastic resilient diaphragm, a dat coil parallel with the diaphragm, an armature having a ortion eX- tending Within the coil, and an e ectro-magnet with one pole on one side oi the coil 9o adjacent the diaphragm and the other pole on the other side of said coil.

9. In electro-magnetic sound producers of the character designated, an elastic resilient diaphragm, a single flat coil parallel with e5' et having an 75 

